In the 1970s, when the House of Commons was debating devolution, the Scottish Labour veteran Tam Dalyell posed a question that has never yet been answered.

Why, he asked, should he, as the member representing Blackburn in West Lothian, be allowed to vote on education in England when the member representing Blackburn in Lancashire could not vote on education in Scotland?

Tam’s famous challenge has become known, over time, as the West Lothian question and it has divided constitutional reformers to this day.

I have enormous respect for Tam Dalyell’s intelligence and integrity, but I am an instinctive devolver of power.

I think we should let people take the decisions that matter most to them at the level closest to them.

That is why I support the moves by Scottish and Welsh Conservatives to devolve more powers to Edinburgh and Cardiff.

But there’s another reason I support devolution. It allows different parties, in different parts of the country, to put their principles into power and lets voters judge, in real-time, which policies are working best.

We’ve already seen over the last few years how Welsh Labour’s approach to the NHS has led to more cutbacks, lengthening waiting lists and poorer outcomes for those in pain. To the point where the party which best represents Bevan’s vision for healthcare in Wales is the Conservatives.

It’s a source of immense sadness to me that this should be so. My wife is Welsh and Swansea is my second favourite city in the world. To see Wales suffer unnecessarily is terrible.

But what is even worse is that the condition which afflicts the Welsh NHS can now be seen to have weakened the Welsh education system.

Wales has a historic attachment to educational excellence and a belief in educational self-improvement which mirrors my own homeland of Scotland. The story of David Lloyd George, the cottage-born boy who lapped up learning at the feet of his uncle Lloyd and became a champion of social progress at Westminster inspired me when I was young.

The writing and rhetoric of working class Welsh heroes, from Nye Bevan to Alan Watkins, Dylan Thomas to Richard Burton remain inspirational.

Which is why Wales’ recent educational decline is so very regrettable.

The most recent international tests showing how our children perform educationally make bleak reading for Wales. According to the Pisa studies conducted by the OECD, Wales has fallen behind the rest of the UK in reading, maths and science for the third time in a row. In maths, Wales fell three places to 43rd whereas England is 25th.

In reading, Wales is 41st compared to England at 23rd. Science saw the biggest fall with Wales dropping six places to 36th, whilst England is 18th.

Pisa’s reading and science assessments showed that almost one in five Welsh students did not achieve the basic level of proficiency needed to actively participate in daily life.

This decline is traceable directly to the Labour Party’s refusal to embrace reforms we’ve been pursuing in England. In fifteen years not a single academy or free school has opened in Wales.

In England, we’ve opened 173 free schools in just three years and there are now 3,923 academies across the country. Since 2010 alone the number of pupils taught in under-performing secondary schools in England has fallen by almost 250,000.

By contrast, the OECD’s conclusion is damning: the Welsh Government lack a ‘long-term vision’ for education or, indeed, an actual strategy to improve schools.

And as well as refusing to embrace reform, in some cases Welsh Labour have actually gone backwards. In 2001, the Welsh Government abolished league tables and in 2004 they scrapped national curriculum tests, ensuring that the Government had no way of holding schools to account and identifying poor performance.

Even Welsh Labour’s Education Minister Leighton Andrews admitted that they’d taken their ‘eye off the ball’ when they scrapped those tests. This wasn’t just incompetent – it was disastrous.

A study from Bristol University showed that pupils in England and Wales were performing at a similar level in 2001. But after dropping national league tables, school performance in Wales has been reduced by two GCSE grades per pupils per year on average.

A quarter of Welsh secondary schools have been rated unsatisfactory by Estyn, the education watchdog. In England just 5% of schools are ‘inadequate’, the equivalent standard.

In the last few months alone, we’ve seen the introduction of a new English GCSE by the Welsh Government cause chaos, with the first exams sat in January yielding shockingly poor results.

And just this week Wales’ independent schools have said they won’t use the new GCSEs designed by the Welsh Labour Government because they aren’t rigorous enough. Instead, they will use the GCSEs we’ve reformed in England.

So Welsh children whose parents are rich enough to buy them an independent school education will benefit from greater rigour while working class children get left behind.

Can that really be what Labour voters want? It certainly doesn’t fit my idea of social justice.

These dire standards are now having an effect on Wales’ teaching workforce. In their report the OECD highlighted Wales’ difficulty recruiting highly qualified teachers.

The number of newly-qualified teachers in Wales fell by a huge 10% last year, the lowest for over a decade. The nation now boasts its smallest teaching workforce since 2004 and the lowest proportion of male teachers since records began.

In contrast, we are driving up the quality of teachers in England. England now has the highest number of teachers with First or 2:1 degrees ever recorded and Teach First was named Britain’s biggest graduate recruiter last year.

Wales is an object lesson in what happens when you abandon reform. Ed Miliband recently told the Welsh Labour Conference that Wales’ Labour Government is ‘proving to the rest of the country the difference that Labour can make.’

It’s certainly doing that on education. Thousands of children falling behind as result of rigid dogma and a refusal to reform – that’s the difference that Labour has made in Wales.

But what makes this tragedy all the more poignant is that every week in the House of Commons the Opposition spokesman who urges me to change course is the Cardiff West Labour MP Kevin Brennan. Kevin is a likeable soul, and as a former teacher he has a passion for education.

But how credible can he, and his party be when the education children are getting in his constituency of West Cardiff is deteriorating because of Labour policy while the education children enjoy in West London is getting better and better thanks to Conservative Policy?

Where Tam Dalyell once asked the West Lothian question of his frontbench, let me ask the West Cardiff question of Labour’s front bench.

Why should anyone let Labour control education policy in England when they have made such a mess of it in Wales?